A. Field of the Invention
The invention relates to wall structure about a high temperature zone and, in particular, a blast furnace stack system for the thermal treatment of material, such as the smelting of ore concentrate.
B. The Prior Art
Typically, in known pyrometallurgical or blast furnace systems, such as disclosed in U.S. Pat. No. 3,555,164, fine-grained metalliferous ore particles are blown into a smelting stack with an oxygen-rich gas (often air). In the smelting stack, the fluid-carried ore becomes calcined and smelted. The resulting gases produced thereby, such as iron monoxide and carbon monoxide, as well as dust particulates, are withdrawn from the smelting stack into a neighboring waste-gas stack. The smelt iron and slag produced from the ore collects at the bottom of the smelting stack in a molten bath, which passes beneath a partition member into a settling furnance for further treatment of the smelt and removal of the slag. If the treated ore is of a sufficiently high sulfur content, then enough heat can be generated by combustion of the sulfide sulfur so that the calcining and smelting operation in the smelted stack may autogenously occur, obviating the need for fuel addition in the smelting stack.
The furnace walls within the smelting stack come into contact with very hot gases as well as molten metal falling to the slag bath. Accordingly, the furnace walls must be made impervious to heat. Prior art techniques for doing this include providing a furnace wall made up of fire-proof stone provided internally with cooling channels containing flows of cooling liquid, such as water, therethrough. However, the incorporation of cooling channels in the fire-proof material results in a weakening of the furnace wall such that the furnace wall is unable to bear the loads necessary for its suspension over the molten bath.